3G

The third generation mobile communication technology (3G), law - are refers to support high-speed data transmission of cellular mobile communication technology. 3G service can simultaneously transmit voice and data information in commonly hundreds of KBPS, rate above. At present, there are four kinds of standard: 3G CDMA2000, WCDMA, td-scdma, WiMAX.

3G module

External 3G module: refers to the outer ShangWangKa, such as: jinwei 3G JWOD2 is often said xinghang 3G wireless USB ShangWangKa. External ShangWangKa mainly with 3G USB interface, mostly in the 200 yuan price. At present China telecom, China mobile, China unicom 3G business in stored must 250-300 words fee) will be giving a. But still some users want to buy, so this site on the clean up this kind of product price.

Due to China telecom, China mobile, China unicom three carriers 3G network, so using different standard below will be supported by these products were marked the web standards. Mobile = td-scdma; Telecom = CDMA2000; Unicom = WCDMA.

External 3G MODEM: embedded industrial-class JWOD2 3G wireless module. JWOD2 weft xinghang using standard industrial standard design, have Chinese text messages transceiver, English SMS transceiver and wireless Internet functions. Provide RS232 standard interface directly with customers, connected, realize short message transceiver function. JWOD2 can be used as finance, water conservancy, environmental protection, electric power, postal, weather, etc.

A, wireless parameters

1, supports UMTS/WCDMA/HSDPA/HSUPA 850/900/1900/2100MHz

2, double-frequency EGSM 850/900/1800/1900MHz

Three, support GPRS/EDGE scale-up 12

4, data rate

HSDPA/HSUPA mode:

To 7.2 Mbps Downlink up

5.76 Mbps to Uplink up

WCDMA mode:

384Kbps Downlink/Uplink up to

EDGE mode:

236.8 Mbps to Downlink up

118Kbps Uplink up to

GPRS mode:

Downlink up to 85.6 Mbps

To Uplink up 42.8 Kbps

CSD mode:

Downlink/Uplink up to 14.4 Kbps

5, support DTMF

6, supporting SMS/Internet functions

7, standard AT command set

Second, technical indices

1, interface:

Standard RS232 serial ports, 110 ~ 230400BPS serial rate

Indicator: has the power and online indicator.

Antenna interface: standard SMA Yin head antenna interface, the characteristic impedance 50 Europe.

SIM card interface: 3V / 1.8 V standard pusher-type using interface.

Power source: standard three core engine power socket.

Voice interface: standard microphone interface (reserve).

2, power supply:

External power supply: DC 12V 500mA

Wide voltage power supply: DC 9-35V

Communication current: 250mA

Standby current: 20mA

3G standard

The international telecommunications union (ITU) in May 2000 sure WCDMA, CDMA2000, td-scdma and WiMAX four mainstream wireless interface standards, writes the 3G technical guidance documents in 2000 international mobile communication project "(" IMT - 2000). CDMA is Code Division Multiple Access (CDMA), is the abbreviation of the third generation mobile communication technology foundation. The first generation of mobile communication system adopts frequency division multiple access (FDMA) simulation, this system modulation method is the main disadvantages of spectrum utilization rate is low, signaling interference voice business. The second generation of mobile communication system mainly USES the TDMA (TDMA) digital modulation mode, improving the system capacity, and adopt independent channels, the performance of the system transfer signaling improved, but TDMA system capacity still limited, handoff properties are still not perfect. CDMA system with its frequency planning large capacity, simple, system frequency reuse, high coefficient anti-multipath ability, communication of good quality, soft capacity, soft handoff characteristics shows that the huge development potential. Introduce 3G respectively under several standard:

W - CDMA

Also called WCDMA, CDMA, also called all Wideband CDMA Direct Spread, meaning called for broadband points yards, which is multiple access based on GSM network 3G technology developed by the European standard, it is put forward, the broadband CDMA technology with Japan proposed broadband CDMA technology basic same, is currently further merge. W - CDMA supporters is mainly by GSM system primarily European manufacturers, Japanese companies are either more or less involved, including euramerican Ericsson, alcatel, nokia, lucent, nortel, and Japan's NTT, Fujitsu, sharp manufacturers. This standard proposed GSM (2G) - GPRS - EDGE - WCDMA (3G) evolution strategy. This system can be mounted on the existing GSM network system provider for more easily concerned can to transition. Expected in GSM system of Asia, is immensely popular for the new technology of acceptance can be quite high. Therefore W - CDMA has inherent market advantage.

CDMA2000

CDMA2000 is by narrowband CDMA (code division multiple access (CDMA) IS95) technology development and to broadband CDMA technology, also called CDMA Multi - Carrier, it is from the north American company proposed for leading qualcomm, MOTOROLA, Lucent and later joined samsung has participation, South Korea now become leader of this standard. This system from narrowband CDMAOne digital standard derivatives, can directly from the original CDMAOne structure upgrading to 3G, construction cost. But now use CDMA area only to Japan, South Korea and North America, so the CDMA2000 than W - CDMA many supporters. But CDMA2000 research technology is currently in each standard, many of the fastest progress 3G mobile phone has first appeared. This standard proposed IS95 (from CDMA CDMA20001x - CDMA20003x 2G) - (3G) evolution strategy. CDMA20001x called 2.5 generation mobile communication technology. CDMA20001x CDMA20003x and the main difference between the multiple carrier technology application, by adopting three carrier makes bandwidth enhancement. China telecom is using this proposal to the transition, and 3G IS95 already built a CDMA network.

Td-scdma

Synchronous Division - a whole called CDMA (code Division multiple access (CDMA)), the portion of synchronization standards formulated by the Chinese mainland 3G standards, alone on June 29, 1999, ministry of science and technology of China telecom original academy (datang telecommunications) put forward to the ITU, but technical invention began in Siemens company, td-scdma with radiation characteristics of low, known as the green 3G. This standard will intelligent wireless, synchronous CDMA and software radio today the international leading technology into which, in spectrum utilization, flexibility, for business support frequency flexibility and cost etc. distinct advantages. In addition, because China mainland huge market, the standard by every major telecoms equipment maker's attention, more than half of global factory shangdu announced can support TD - td-scdma standards. This standard suggested not pass through the intermediate link, 2.5 and directly to the 3G transition, very suitable for GSM system upgrade to 3G. Military communications network is the central task of td-scdma system.

WiMAX

WiMAX name is Microwave Access global interchange (Interoperability for Microwave Access) number, also known as 802 · 16 wireless intracity networks, is also a kind of for enterprise and home users to provide "last mile" broadband wireless connection scheme. Will this technology and need authorization or exemption authorized microwave equipment after combining, due to lower costs, will expand broadband wireless market, improve the perception of enterprise and the service provider. On October 19, 2007, in the international telecommunications union in Geneva wireless communication plenary meeting, after most countries voted, WiMAX is officially approved for a following WCDMA, CDMA2000 and td-scdma 3G after the fourth global standard.